This invention relates generally to the art of counters which indicate number of rounds remaining in firearm magazines, and most particularly, to such counters showing an exact count of rounds in a magazine while the magazine remains in the firearm.
Various devices have been devised which include means for revealing the contents of a magazine. Several patents have been granted for devices which utilize either a colored mark on a follower or an audible alarm to indicate whether a magazine is full or empty.
U.S. Pat. No. 4,587,756 to Jakubaschk et al. discloses a magazine which includes a colored indicator to show the magazine is ready to fire. U.S. Pat. No. 4,109,401 to Musgrave describes a follower fashioned of radiant color to approximately count, according to its position, the number of cartridges in an opaque magazine which includes numbers thereon which correspond to each position of cartridges therein.
An audible signal for indication of an empty magazine is used in U.S. Pat. No. 4,142,313 to Musgrave wherein a noise is made when a magazine has been depleted of its contents. Similar audible indicators are disclosed in U.S. Pat. Nos. 4,216,601 to Musgrave and 4,219,953 also to Musgrave.
While these prior art devices perform well for their intended applications, there is no satisfactory device for counting rounds in a firearm magazine without removing the magazine from the weapon.